Combination steel and die casting cleaning process



Se t. 29, 1953 J. A. THOMAS 2,653,883

COMBINATION STEEL AND DIE CASTING CLEANING PROCESS I Filed Dec. 3, 1951DIE. CA5T|-6 J UL /U-S A THOMAS INVENTOR.

'fm w A TTORNEYS VBY Patented Sept. 29, 1953 COIHBINATION STEEL AN DDIECASTING swar s R E Julius A. Thomas, Monroe, Mich., assignor to- FordMotor Company, Deal-born, Mich., a corporation of Delaware ApplicationDecember 3, 1951, Serial N 0. 259,651

3 Claims.

This invention is concerned with the electroplating industry and moreparticularly with that segment of the metal finishing industry in whichlarge numbers of similar pieces are automatically electroplated.

In the automotive industry it has been found commercially desirable toprotect and decorate both fabricated steel parts and zinc base die castparts by chromium plating. Conventional chromium plating involves firsta flash or strike of copper followed by a heavier copper plate uponwhich is superimposed a nickel plate. Finally a thin flash of chromiumis added to the nickelplated surface. In this plating procedure, as inall plating procedures, it is necessary that surface to be covered bemeticulously cleaned before plating. The ordinary zinc base die castingsare usually subjected to a dip in a tank containing water or otheraqueous base cleaning solution, heated to about 150 F. upon which isfloated a layer approximately 1 inch thick, of a Water insolublehydrocarbon or other grease solvent having a boiling point rangecorresponding to ordinary kerosene. This is the first step in thecleaning process and is usually followed by a dip in a heated alkaliphosphate bath.

This procedure is quite satisfactory for die castings but if it be usedupon fabricated steel parts, unsatisfactory results are certain toensue. Fabricated steel parts invariably contain crevices and seamsproduced in th manufacturing operations and particularly in spot-weldingprocedures. When such a part is passed through a layer of kerosene, thismaterial fills such crevices and it is commercially impracticable toremove this kerosene with the thoroughness necessary to producesatisfactory plated articles. In the past this difficulty has requiredthat separate cleaning lines be employed for steel parts and die castparts despite the obvious economy which would be effected if both typesof parts could be cleaned in the same apparatus.

The instant invention has been developed to enable steel and zinc diecastings to be cleaned in the sam apparatus. This invention is probablybest understood from a study of the attached drawing which is a verticalsection taken through the length of a cooling tank.

In this drawing a steel tank is indicated at It) and is filled to adepth of about six feet with a layer of water H. A layer of kerosene [2about one inch in thickness is floated upon the top of layer of water H.Adjacent one end of this tank are located air nozzles I3. These nozzlesare positioned about twelve inches beneath the level of thkerosene-water interface and are pointed upwards. When the tank is inoperation the water is heated to about F. and a vigorous stream of airis forced through nozzles l3. This vigorous stream of air violentlyagitates the end of the tank in which the nozzles I3 are located andeifectively prevents the layer of kerosene l2 from extending over thatportion of the tank. Instead of occurring as a separate layer, thekerosene in this section of the tank occurs as an emulsion scatteredthroughout that portion of the tank.

In th operation of this tank, the operator permits the die cast parts todescend into the hot water through the unbroken kerosene layer occurringin all parts of the tank remote from nozzles l3. In this way advantageis taken of the very potent grease dissolving action of hot kerosene.When steel parts are to be cleaned, the operator causes these parts toenter and leave the cleaning tank only through that part of the tank inwhich the layer of kerosene has been dissipated by the action of thenozzles l3. In this Way the crevices of the steel parts will fillpredominantly with water rather than kerosene and only sufficientkerosene in emulsion form contacts the steel part to perform thenecessary cleaning operations. In the drawing the path of the die castparts is indicated by the lower lines and the path of the steel parts bythe upper lines. However, th path of the die cast articles may be variedif convenient, so that they leave the tank through the kerosene layer orthe emulsified area.

By so operating this apparatus, it is possible to simultaneously employthe same cleaning and plating line to plate steel and die cast parts andavoid the expense of individual lines.

I claim as my invention:

1. The process of cleaning steel and die cast articles in a singlecontainer comprising filling said container with an aqueous basecleaning solution upon which is floated a layer of a water insolublegrease solvent, agitating one portion of the surface area of thecontainer sufiiciently vigorously to substantially completely dissipatethe grease solvent layer over the agitated area and emulsify the greasesolvent, immersing the die cast articles into the container through anunagitated area, removing the die cast articles and immersing andremoving the steel articles only through the agitated area.

2. The process of cleaning steel and die cast articles in a singlecontainer comprising filling said container with an aqueous basecleaning solution upon which is floated a layer of a water insolublegrease solvent, agitating one portion of the surface area by means ofair Jets sufliciently vigorously to substantially completely dissipatethe grease solvent layer over the agitated area immersing die castarticles into the container through the unagitated area, removing thedie cast articles and immersing and removing the steel articles onlythrough the agitated area.

3. The process of cleaning steel and die cast articles in a singlecontainer comprising filling said container with an aqueous basecleaning solution upon which is floated a layer of water insolublegrease solvent, agitating one portion of the surface area by means of anair stream introduced about twelve inches below the surface and in avertical direction, immersing die cast articles into the containerthrough the unagitated area, removing the die cast articles andimmersing and removing th steel articles through the agitated area.

JULIUS A. THOMAS.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,389,488 Dailey Nov. 20, 1945 2,538,340 Tomek Jan. 16, 1951

1. THE PROCESS OF CLEANING STEEL AND DIE CAST ARTICLES IN A SINGLECONTAINER COMPRISING FILLING SAID CONTAINER WITH AN AQUEOUS BASECLEANING SOLUTION UPON WHICH IS FLOATED A LAYER OF A WATER INSOLUBLEGREASE SOLVENT, AGITATING ONE PORTION OF THE SURFACE AREA OF THECONTAINER SUFFICIENTLY VIGOROUSLY TO SUBSTANTIALLY COMPLETELY DISSIPATETHE GREASE SOLVENT LAYER OVER THE AGITATED AREA AND EMULSIFY THE GREASESOLVENT, IMMERSING THE DIE CAST ARTICLES INTO THE CONTAINER THROUGH ANUNAGICATED AREA, REMOVING THE CAST ARTICLES AND IMMERSING AND REMOVINGTHE STEEL ARTICLES ONLY THROUGH THE AGITATED AREA.